From: Brian Masney <bmasney@redhat.com>
To: Johan Hovold <johan+linaro@kernel.org>
Cc: "Stanimir Varbanov" <svarbanov@mm-sol.com>,
"Lorenzo Pieralisi" <lpieralisi@kernel.org>,
"Andy Gross" <agross@kernel.org>,
"Bjorn Andersson" <andersson@kernel.org>,
"Konrad Dybcio" <konrad.dybcio@somainline.org>,
"Bjorn Helgaas" <bhelgaas@google.com>,
"Rob Herring" <robh+dt@kernel.org>,
"Krzysztof Kozlowski" <krzysztof.kozlowski+dt@linaro.org>,
"Krzysztof Wilczyński" <kw@linux.com>,
"Manivannan Sadhasivam" <mani@kernel.org>,
"Krishna chaitanya chundru" <quic_krichai@quicinc.com>,
quic_vbadigan@quicinc.com, linux-arm-msm@vger.kernel.org,
linux-pci@vger.kernel.org, devicetree@vger.kernel.org,
linux-kernel@vger.kernel.org
Subject: Re: [PATCH 2/2] PCI: qcom: Add basic interconnect support
Date: Thu, 20 Oct 2022 12:49:54 -0400 [thread overview]
Message-ID: <Y1F8MqeHxj5IaLtx@x1> (raw)
In-Reply-To: <20221017112449.2146-3-johan+linaro@kernel.org>
On Mon, Oct 17, 2022 at 01:24:49PM +0200, Johan Hovold wrote:
> On Qualcomm platforms like SC8280XP and SA8540P interconnect bandwidth
> must be requested before enabling interconnect clocks.
>
> Add basic support for managing an optional "pcie-mem" interconnect path
> by setting a low constraint before enabling clocks and updating it after
> the link is up.
>
> Note that it is not possible for a controller driver to set anything but
> a maximum peak bandwidth as expected average bandwidth will vary with
> use case and actual use (and power policy?). This very much remains an
> unresolved problem with the interconnect framework.
>
> Also note that no constraint is set for the SC8280XP/SA8540P "cpu-pcie"
> path for now as it is not clear what an appropriate constraint would be
> (and the system does not crash when left unspecified currently).
>
> Fixes: 70574511f3fc ("PCI: qcom: Add support for SC8280XP")
> Signed-off-by: Johan Hovold <johan+linaro@kernel.org>
Reviewed-by: Brian Masney <bmasney@redhat.com>
prev parent reply other threads:[~2022-10-20 16:50 UTC|newest]
Thread overview: 10+ messages / expand[flat|nested] mbox.gz Atom feed top
2022-10-17 11:24 [PATCH 0/2] PCI: qcom: Add basic interconnect support Johan Hovold
2022-10-17 11:24 ` [PATCH 1/2] dt-bindings: PCI: qcom: Add SC8280XP/SA8540P interconnects Johan Hovold
2022-10-19 14:37 ` Krzysztof Kozlowski
2022-10-20 7:57 ` Johan Hovold
2022-10-20 12:29 ` Krzysztof Kozlowski
2022-10-21 6:40 ` Johan Hovold
2022-10-17 11:24 ` [PATCH 2/2] PCI: qcom: Add basic interconnect support Johan Hovold
2022-10-19 14:32 ` Brian Masney
2022-10-19 14:45 ` Johan Hovold
2022-10-20 16:49 ` Brian Masney [this message]
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